Used vehicular tires are difficult to dispose of because they occupy a vast amount of space in a landfill or other disposal area and disintegrate at a much slower rate than other refuse. Most landfills charge high fees for used tire disposal and some landfills will not even accept them. Alternatively, they cannot be efficiently burned in an energy conversion process or otherwise recycled in their present form. However, when used fires are reduced to rubber strips of a smaller size, e.g. 1/2".times.2" (1.27 cm.times.5.08 cm), they can be used as fuel in power producing plants. If the strips are further reduced to a fine granular powder, the powder can be used as an additive in the manufacture of asphalt as well as other uses, e.g. rubber mats, etc. Federal law and regulations currently mandate that by 1994 a specified amount of recycled rubber be added to all new asphalt. Thus it has become very desirable to recycle used tires to keep them out of landfills while utilizing them for the production of energy or for the manufacture of asphalt and other suitable compounds or mixtures. There are machines and processes currently on the market which perform these recycling functions; however, none do so in the same novel, effective, and efficient way as this tire shredder and process.
The primary shredder of this tire shredding mechanism cuts the tires at the line to line interface of the edge of the bottom land of the first rotary cutter tooth and the edge of the top land of the second cutter tooth. Unlike the prior art, which cuts the tires in a scissor-like manner along the side edges of each tooth, the primary shredder requires approximately 90% less horsepower to achieve the same results. The unique and novel design of the tire pulverizing or grinding machine efficiently reduces the rubber while separating the metal wire and polyester fibers from the recycled rubber. Its grinding disks are designed and the speed of their rotation is set so that the rubber pieces are not burned as they are processed. Thus the invention produces unburned recycled rubber which does not contain metal wires or fibers commonly used in the construction of vehicular tires.